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16 Nov 2024 03:24:08 EST (-0500)
  "Tree" algorithms (Message 1 to 4 of 4)  
From: Lawrence W
Subject: "Tree" algorithms
Date: 12 Jan 2006 09:30:01
Message: <web.43c6677fa25a577e8a5251970@news.povray.org>
Its been a while since I posted anything here, and there was only a few
anyway.  Nonetheless, once a Pover, its hard to stay away for long.

I'd like to creat my own tree macro, and to start I've got a cone shaped
object made up of a stack of individual cones.  My goal is to create a tree
with cone shaped sections that branch out from a central trunk.  I'm
thinking this would be a recursive deal with the entire tree concept
repeating on each branch until I hit a certail threshold.

Is this possible?  Am I dumb to try to recreate the wheel?  I really want to
do this task for myself, in order to better understand the PovRay SDL.  So
here's what I've got so far.  The cone on the right is the tree so far; the
cone on the left is the reference cone for height, and the cone in the
middle is the base unit that I started from.  Any help is extremely
appreciated.  Thanks.


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From: Doctor John
Subject: Re: "Tree" algorithms
Date: 12 Jan 2006 09:45:17
Message: <43c66b7d$1@news.povray.org>
"Lawrence W" <lwi### [at] csicablenet> wrote in message 
news:web.43c6677fa25a577e8a5251970@news.povray.org...
> Its been a while since I posted anything here, and there was only a few
> anyway.  Nonetheless, once a Pover, its hard to stay away for long.
>
> I'd like to creat my own tree macro, and to start I've got a cone shaped
> object made up of a stack of individual cones.  My goal is to create a 
> tree
> with cone shaped sections that branch out from a central trunk.  I'm
> thinking this would be a recursive deal with the entire tree concept
> repeating on each branch until I hit a certail threshold.
>
> Is this possible?  Am I dumb to try to recreate the wheel?  I really want 
> to
> do this task for myself, in order to better understand the PovRay SDL.  So
> here's what I've got so far.  The cone on the right is the tree so far; 
> the
> cone on the left is the reference cone for height, and the cone in the
> middle is the base unit that I started from.  Any help is extremely
> appreciated.  Thanks.
>
I don't want to pour pour cold water on your project, but it seems to me 
that Arbaro, Pov-tree and/or Tom-tree have already beaten you to the punch 
in creating organic-looking trees. However, as an exercise in refreshing 
your understanding of the SDL - not a bad idea. Now if you could produce a 
macro to generate isosufaces that mimic trees you be onto a real winner :-))
BTW, welcome back. I too was away for a time but its hard to say no when 
POVray sidles up to you, slips its little hand into yours and says "Just 
once more, for old times sake".

John
-- 
Run Fast
Run Free
Run Linux


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From: Tim Nikias
Subject: Re: "Tree" algorithms
Date: 12 Jan 2006 09:58:08
Message: <43c66e80@news.povray.org>
> Is this possible?  Am I dumb to try to recreate the wheel?

Of course it's possible, others have already tried it and succeeded.
Personally, I don't think you're dumb for attempting to script something
yourself, heck, I'm doing that all the time!

I've had a go at trees myself some time ago, and found that you really need
to plan things ahead. Povray doesn't come with all kinds of nice goodies
like creation of lists or such, only with single values and arrays, and
those are even very rigid in that they only accept a single type of
information. So, creating a properly balanced tree which does look quite
realistic is some major task you set yourself to do.

You've also got to keep the overhead in mind. Rendering your tree with tons
of cones will make it a very slow render, along with high parsing times
you'll quickly get to the point where you don't get your results fast enough
to keep a steady, working progress.

But all those are just things I wanted to point out in case you didn't think
of them yourself. It's never dumb to attempt something in order to learn.
All I'm trying to say is that *maybe* you should pick something with a
better prospect. Better for the ego. :-)

Good luck,
Tim

-- 
aka "Tim Nikias v2.0"
Homepage: <http://www.nolights.de>


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From: Mike Williams
Subject: Re: "Tree" algorithms
Date: 12 Jan 2006 10:30:18
Message: <VwimzBAxUnxDFwOI@econym.demon.co.uk>
Wasn't it Lawrence W who wrote:
>Its been a while since I posted anything here, and there was only a few
>anyway.  Nonetheless, once a Pover, its hard to stay away for long.
>
>I'd like to creat my own tree macro, and to start I've got a cone shaped
>object made up of a stack of individual cones.  My goal is to create a tree
>with cone shaped sections that branch out from a central trunk.  I'm
>thinking this would be a recursive deal with the entire tree concept
>repeating on each branch until I hit a certail threshold.
>
>Is this possible?  Am I dumb to try to recreate the wheel?  I really want to
>do this task for myself, in order to better understand the PovRay SDL.  So
>here's what I've got so far.  The cone on the right is the tree so far; the
>cone on the left is the reference cone for height, and the cone in the
>middle is the base unit that I started from.  Any help is extremely
>appreciated.  Thanks.

It's a useful exercise in writing recursive macros, but other people
have discovered that a realistic tree made from a large number of cones
is rather slow to render. Replacing the cones with mesh fragments that
approximate the cone shapes, and joining all those fragments into one
large mesh object can produce realistic trees in a reasonable render
time.

-- 
Mike Williams
Gentleman of Leisure


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